Adherence is defined as ‘the extent to which a person’s behaviour coincides with medical or health advice’. Non-adherence to therapeutic regimens is a common and expensive problem in patients with chronic diseases including systemic lupus erythematosus (SLE) and is associated with a higher risk of flares, morbidity, hospitalisations and poor renal outcomes.^{1 2} Non-adherence is also very difficult to evaluate.^3–5

Hydroxychloroquine (HCQ), an important medication in SLE with an excellent benefit:risk ratio, has a long half-life and it can be measured in blood. Undetectable or very low levels of blood HCQ is then a simple, objective and reliable marker of non-adherence in SLE patients.^{1 4 5}

Levels of HCQ and then HCQ non-adherence should be routinely and repeatedly assessed. If severe non-adherence is unmasked, a non-judgmental and open discussion must take place to improve adherence as much as possible. This task is not simple, but particularly important and some tips will be discussed (table 1).⁵

References

1. Costedoat-Chalumeau N, et al. Adherence to treatment in systemic lupus erythematosus patients. Best Pract Res Clin Rheumatol 2013 Jun;27(3):329–340.

2. Feldman CH, et al. Medication nonadherence is associated with increased subsequent acute care utilization among medicaid beneficiaries with systemic lupus erythematosus. Arthritis Care Res (Hoboken) 2015 Dec;67(12):1712–1721.

3. Osterberg L, Blaschke T. Adherence to medication. N Engl J Med 2005 Aug 4;353(5):487–497.

4. Costedoat-Chalumeau N, et al. A prospective international study on adherence to treatment in 305 patients with flaring SLE: assessment by drug levels and self-administered questionnaires. Clin Pharmacol Ther 2019 Aug;106(2):374–382.

5. Costedoat-Chalumeau N, Houssiau FA. Improving medication adherence in patients with lupus nephritis. Kidney Int 2021 Feb;99(2):285–287.

Learning Objectives

• Recognise the frequency and consequences of non-adherence

• Describe methods to evaluate non-adherence

• Analyse blood hydroxychloroquine levels

• Improve the way we discuss non-adherence with our patients